/*
 * Copyright (C) 2018 Square, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.unixdomainsockets;

import java.io.File;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.nio.channels.ClosedChannelException;
import javax.net.ServerSocketFactory;

import jnr.unixsocket.UnixServerSocketChannel;
import jnr.unixsocket.UnixSocketAddress;
import jnr.unixsocket.UnixSocketChannel;

/**
 * Impersonate TCP-style ServerSocketFactory over UNIX domain sockets.
 */
public final class UnixDomainServerSocketFactory extends ServerSocketFactory {
    private final File path;

    public UnixDomainServerSocketFactory(File path) {
        this.path = path;
    }

    @Override
    public ServerSocket createServerSocket() throws IOException {
        return new UnixDomainServerSocket();
    }

    @Override
    public ServerSocket createServerSocket(int port) throws IOException {
        return createServerSocket();
    }

    @Override
    public ServerSocket createServerSocket(int port, int backlog) throws IOException {
        return createServerSocket();
    }

    @Override
    public ServerSocket createServerSocket(
            int port, int backlog, InetAddress inetAddress) throws IOException {
        return createServerSocket();
    }

    final class UnixDomainServerSocket extends ServerSocket {
        private UnixServerSocketChannel serverSocketChannel;
        private InetSocketAddress endpoint;

        UnixDomainServerSocket() throws IOException {
        }

        @Override
        public void bind(SocketAddress endpoint, int backlog) throws IOException {
            this.endpoint = (InetSocketAddress) endpoint;

            UnixSocketAddress address = new UnixSocketAddress(path);
            serverSocketChannel = UnixServerSocketChannel.open();
            serverSocketChannel.configureBlocking(true);
            serverSocketChannel.socket().bind(address);
        }

        @Override
        public int getLocalPort() {
            return 1; // A white lie. There is no local port.
        }

        @Override
        public SocketAddress getLocalSocketAddress() {
            return endpoint;
        }

        @Override
        public Socket accept() throws IOException {
            try {
                UnixSocketChannel channel = serverSocketChannel.accept();
                return new TunnelingUnixSocket(path, channel, endpoint);
            } catch (ClosedChannelException e) {
                SocketException exception = new SocketException();
                exception.initCause(e);
                throw exception;
            }
        }

        @Override
        public void close() throws IOException {
            serverSocketChannel.close();
        }
    }
}
